Double-acting pin-puller.



F. H. SKINNER.

DOUBLE ACTING PIN FULLER.

APPLICATION FILED MAY 26, 1909.

1,072,520, Patented Sept. 9, 1913.

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cOLUMBlA P'LANUGRAPH co., WASHINGTON. D. c.

FRANK H. SKINNER, 0F CHIGAGO, ILLINOIS.

DOUBLE-ACTING PIN-FULLER.

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Specification of Letters Patent.

Patented Sept. 9, 1913.

Application filed May 26, 1909. Serial No. 498,515.

To all whomc't may concern:

Be it known that I, FRANK H. SKINNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of.

Illinois, have invented certain new and useful Improvements 1n Double-Acting Pm- Pullers, of which the following is a specifi-' cation.

My invention relates to the art of dentistry and has particular reference to improvements in crown pin pulling devices.

The object of my invention is to provide improvements in that type of my inventions in which the reciprocal forces are all operated simultaneously by a single agency and with a minimum consumption of time and space, and the lnventlon consists 1n the novel construction, combination and arrangement of parts hereinafter described in detail, illustrated in the drawings and incorporated in the appended claims, in which no claim is made to the construction disclosed in my copending application N 0. 496,619.

In the drawing Figure 1 is a perspective view of an instrument embodying my inven tion, held between an operators fingers. Fig. 2 is a side elevation on a greatly enlarged scale, showing the instrument itself partly in section with a removed crown-pin in the grip of its jaws taken from a tooth shown in dotted lines. Fig. 3 is a vertical section of the instrument and Fig. 4 is a horizontal section taken on line XX of Fig. 2. In the several views 2 and 3 represent a pair of jaws pivoted together at 4.

These jaws are formed with halved portions or disks 5 and 6 which project from the inner edges of the jaws proper and overlie each other so that they form a flush, rabbet or lap joint.' The beaks 8 and 9 of the jaws are normally pressed together by means of a spring 9 interposed between the jaws intermediate of their fulcrum 4 and their power ends. The latter ends, 10 and 11, are connected by toggle links 12 and 13 and a nut 14. The latter has cars 15 and 16 which have mortises in which the inner ends of the toggle links are received. 'The links are pivoted to, respectively, these ears and the power ends of the jaws or levers 2 and 3. A forked post 17, 18, formed by bending a piece of steel upon itself, straddles thejoint of the jaws and is guided at its lower end by means of the pivot 4 engaging slots. 19 in the members of the fork or post 17, 18. The pivot 4 is provided with heads 20 and 21 which prevent displacement of the post members from the pivot. To the upper end or bend 22 of the post the lower end of a screw 23 is pivoted. This screw has threaded engagement with the nut 14. The screw is provided with a knurled head 24 by means of which it is rotated by the operator. Near the lower ends or tips of the post its members are supported against spreading apart by means of a cross-pin 25 the ends of which are secured to the respective members of the post.

In Figs. 2 and 3 is shown a pin 26 held in the grip of the jaws as it appears when withdrawn from a pin aperture 27 in a tooth 28.

Considering the mechanism thus described it will be noticed that the construction and arrangement involves only simple and comparatively inexpensive parts and operations in their manufacture. Practically the whole instrument may be formed by then The single pivot 4 serves both the jaws and the post, andthe latter conceals the joint of the jaws and the spring 9, giving a neat and simple exterior appearance to the instrument. It may also be manufactured at a comparatively low cost to meet the demands of the cheaper trade.

The operation of the instrument is as folQ lows: The projecting end of a pin or post 27 cemented into a root cavity is engaged by the jaws by pressing them together wit-h the grip shown in Fig. 1, which is facilitated by simultaneously pressing down upon the screw 14 and thus using the toggle-link force to expand the beaks of the jaws. The post is then advanced from its retracted position shown in Fig. 1 against the root of the tooth 28 by turning the knurled head 24. As

the tips of the post come into contact with the root 28 the resistance offered to the post will tend to straighten out the toggle links thus increasing the initial grip provided by I the spring 9 in the same proportion as the resistance offered by the root to the advancement of the post. As the screw continues to advance in the nut 14 the reaction of the force'will be communicated to the nut 14 and as the post can advance no farther with respect to the root of the tooth the jaws will be. forced to recede with the pin in their grip. If the pin is very firmly cemented in the cavity 27 the grip of the jaws will be made correspondingly firm through the toggle links. This automatic adjustment of the grip insures asufficient gripping force to prevent the jaws from acidentally slipping oil' the pin andoblige the operator to take a fresh grip, all of which, when it occurs, occasions that much additional jarring of the patient. As the gripping force of the jaws, their pulling force, and the pushing force of the post are all accomplished at once by manipulation of the knurled head and from a position in line with the aXis of the root, the operation of'eXtracting a pin is muchmorerapid, and for the other reasons stated, much more certain than when separate operating means are provided for the post and jaws. Another very important advantage gained is that the operator is re lieved of perhaps the hardest part of the usual operationthat of tightening the aws sufiiciently upon the pin before applying the reciprocal forces to the jaws and post to extract the pin after it is once gripped.

I claim as my invention 1. The combination with a pair of jaws, of a post, a pin upon which said jaws are pivotally movable, means for guiding said post upon said pin, and means for moving said jaws and post.

' 2. The combination with apair of jaws, of a slotted post, a pin upon which said jaws are pivotally movable and upon which said postis longitudinally movable, and means for moving said jaws and post.

8; The combination with a pair of jaws,

of a forked and slotted post embracing the sides of said aws, a fulcrunrpin upon which said jaws are pivotally mounted and upon which said post is slidably mounted, and a means for moving said post which imparts a gripping movement to said jaws. 4. The combination with a pair of jaws having a disk-joint therebetween, of a pivotpin for said joint, a forked post embracing said joint, and neans for actuating said jaws and post simultaneously.

5. The combination with a pair of jaws pivoted together between their ends, of a post, a toggle joint for moving said jaws, and a screw having threaded connection with said joint and swiveled connection with said post, whereby bot-h jaws and post are movable simultaneously.

Intesti'mony whereof I have hereunto set my hand in the presence of two witnesses- FRANK H. SKINNER.

Witnesses:

v M. C. ALLEN, H. W'ALDMAN.

Games of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

